Among the various forms of passive restraint belt systems are those in which both a shoulder belt and a lap belt are transferred between occupant-restraining and occupant-releasing positions in response to closing and/or opening of the vehicle door. In some of those systems, a shoulder belt leads from a retractor mounted on the vehicle roof above and behind the passenger through a transfer guide that moves between a rearward position and a forward position along a path generally above the door and thence downwardly and inwardly across the seat. A lap belt leads from a retractor mounted on the lower rear corner of the door through a guide that moves generally upwardly, and preferably forwardly as well, along the door from a position near the retractor and leads from the guide across to the inboard side of the seat. In some of those systems the lap and shoulder belts are portions of a continuous belt, such portions being delineated at a D-ring on the inboard side of the seat through which the continuous belt passes.
Many passive restraint belt systems provide for emergency release of the belt system in the event of a malfunctioning or disabling of the system. For example, if the door cannot be opened after an accident, it is important that the restraint belt can be disconnected so that the passenger can leave or be taken from the vehicle. In systems of the type described above, it has been proposed that the continuous belt be secured at the inboard side of the seat by means of a buckle. When the buckle is released, however, the continuous belt still remains connected between the retractor on the roof and the retractor on the door. If the vehicle door can be opened, the still attached belt will extend down from the roof to the door and present a hindrance to an occupant who tries to leave the vehicle; he may catch his body or his clothing on the belt and thereby be endangered. Moreover, the tension applied to the belt by the retractors hinders the free opening of the door, even though it is desirable that the escape of the passenger be made as easy as possible in an emergency situation. If the door cannot be opened, it may be necessary for the passenger to escape through the window, in which case the belt still presents a hindrance to the passenger's escape because it extends across the rear part of the window.